Active Minimization of Acoustic Energy Density to Attenuate Radiated Noise from Enclosures

Salt Lake Community College

The noise produced by mechanical equipment can be an annoyance as well as a health and safety concern. One application where noise reduction has become important is in diesel power generators. Two methods for the reduction of noise exist: passive and active noise control. In this project active noise control (ANC) is applied to the problem of noise radiating from diesel generator enclosures. The purpose of this research is to show that the active minimization of energy density within an enclosure can lead to a global reduction of the externally radiated noise. Two underlying questions will be answered in this research. Can the noise radiated from a diesel generator enclosure be effectively controlled by minimizing the energy density within? If so, does controlling the noise within the enclosure provide a global reduction? Tests using a filtered-x LMS based adaptive ANC algorithm modified to minimize energy density (ED) have been conducted. These results show that A-weighted sound pressure levels (SPL) outside of a generator enclosure can be reduced by minimizing energy density within.